Device for exchanging heat comprising a plate stack and method for producing said device

ABSTRACT

A device for exchanging heat has a plate stack of at least a first, a second, and a third plate. The three or more plates are stacked one on top of the other and have recesses which are arranged in a regular pattern on a plane of the respective plates. The first and the second plates as well as the second and the third plates are stacked in such a manner that each adjacent plate forms at least one common cooling channel, which is accessible to a fluid, running in a direction on the plane of plates. The two or more cooling channels are formed by way of recesses, which partially but not entirely overlap, in the adjacent plates. The one or more cooling channels of the first and second plates are entirely spatially separated from at least one cooling channel of the second and third plates.

The present invention relates to a device for exchanging heat and to a method for producing said device. The device features a plate stack comprising at least a first, a second and a third plate. The at least three plates are stacked above one another and have recesses which are embodied to run right through the entire thickness of the respective plate.

The recesses are arranged in one plane of the respective plate in the shape of a regular pattern.

In many applications, such as obtain in many electrical machines for example, heat occurs during the transport and conversion of electrical current. The heat can have a negative effect on the operation of the electrical device and under some circumstances can result in the destruction of the device. In order to prevent this, facilities for dissipation of the heat are provided in the devices. One possible facility is provided by cooling plates, as are known from DE 10 2006 036 833 A1 for example. The cooling plates consist of a stack of plates, which is constructed from at least two plates with recesses. The plates are arranged such that some of the recesses overlap and form a cooling channel. A fluid, e.g. water which flows through the cooling channel, cools the plate and transports superfluous heat out of the device.

A problem with the facility described is the temperature distribution within the cooling plate. This means that a wide temperature difference prevails between the entry and the exit of the cooling fluid into and out of the cooling plate. With temperature-sensitive devices this can have a negative effect on their correct operation.

The object of the present device is to specify a cooling device in which the aforementioned problems are at least ameliorated. A particular object is to specify a device for exchanging heat which makes it possible to make the temperature more uniform in a device. It is also an object of the invention to specify a method for producing the device.

The specified object is achieved in relation to the device for exchanging heat with the characteristics of claim 1 and in relation to the method for producing the device with the characteristics of claim 11.

Advantageous embodiments of the inventive device and of the method for producing the device emerge from the assigned dependent subclaims in each case. In this case the features of the subordinate claims can be combined with features of a respective assigned subclaims or preferably also with features of a number of assigned subclaims.

The inventive device for exchanging heat has a plate stack comprising at least a first, a second and a third plate. The at least three plates are stacked above one another and have recesses which are embodied to run right through the entire thickness of the respective plates. The recesses are arranged in one plane of the respective plate in the shape of a regular pattern. The first and the second plate as well as the second and the third plate adjoin each other and/or are stacked above one another so that the adjacent plates each embody at least one cooling channel accessible for a fluid in one direction in the plate plane. The at least two cooling channels are embodied with the aid of recesses arranged to overlap partly, but not completely in the adjacent plates. The at least one cooling channel of the first and the second plate is completely spatially separated from the at least one cooling channel of the second and the third plate.

The embodiment of separate cooling channels enables a fluid to be introduced from different sides of the device and to remove heat in a contraflow principle from the device for example. The inflow of the fluid for cooling from different sides achieves an evening-out of the cooling effect. A temperature gradient between entry and exit of the fluid in the device is reduced. The device is cooled more evenly in its spatial extent. As an alternative, with a contraflow principle, the device can be used as a heat exchanger between two fluids at different temperatures.

Preferably the recesses of the plate can have an identical shape, especially a Y shape. In such cases the Y-shape can be composed of identical parts turned through 120 degrees respectively. In adjacent plates the recesses can be arranged so that they only overlap in the area of the ends of the Y-shape. With this shape of recess the device can be produced in an especially simple manner and the recesses can easily be made to overlap.

Each end of a Y-shaped recess of a plate can be arranged overlapped respectively with one end of Y-shaped recess of an adjacent plate, especially with precisely one end of a Y-shaped recess of an adjacent plate in each case. The cooling channels formed exhibit favorable flow conditions with this arrangement.

A plate can be constructed from a number of identically-shaped subplates stacked above one another and covering the same area. In relation to cooling surfaces with edge lengths in a range of a few centimeters up to around one meter, the thickness of the plate can range between 0.5 millimeters-20 mm and the channels can have a thickness in the range of 0.5 mm to 20 mm. Very small coolers or very large cooling plates can have correspondingly modified channel measurements.

The plates can consist of a metal, especially magnetizable iron. Furthermore the plates can be coated entirely or partly with an electrically-insulating varnish and/or be electrically insulated in relation to one another.

The plate stack can be part of the generator or of a motor and/or part of a rotor or a stator.

The plates can consist of a metal, especially aluminum or copper.

The plate stack can be used for cooling of electrical power components, such as for cooling of electrical energy accumulators or power electronics components for example.

An inventive method for producing a previously described device is produced by at least three plates being stacked one above the other to form a plate stack such that at least a first cooling channel is produced right through a first and through a second plate of the plate stack. At least one second channel, completely separated spatially from at least the first cooling channel, is made right through the second and a third plate of the plate stack. The cooling channels are formed in at least one direction in one plate plane by recesses in the at least three plates. The recesses of adjacent plates are arranged partly but not completely overlapping.

The recesses can be punched and/or drilled and/or milled and/or etched out of the plates or embodied with the aid of a laser.

The recesses in each of the plates can be arranged in a plane of the respective plate in the shape of a regular pattern. In such cases the first and the third plate are embodied with the same pattern rotated in relation to each other by 90 degrees. The second plate arranged between the first and the third plate is embodied with a pattern which produces an overlaying of the pattern of the first plate with the pattern of the third plate, especially with a displacement of the two patterns in relation to each other by a half spacing of the recesses of a plate in relation to each other.

All plates of the plate stack can be arranged so that recesses of the adjacent plates are mutually overlapping and do not cover the same area.

The plates can be joined to one another by gluing and/or by snap-lock connection and/or by soldering and/or by screwing.

The cooling channels formed by the recesses can have a fluid, especially air, water or oils, frost-protection and corrosion protection agents, flowing through them.

The at least two cooling channels can also each have a fluid flowing through them, whereby the at least two fluid flows differ in their temperature and an exchange of heat occurs via the plates between the fluids separated from one another.

The advantages described here associated with the inventive device are obtained for the inventive method for producing the device.

Forms of embodiment of the invention with advantageous developments in accordance with the features of the dependent claims are explained in greater detail with reference to the following drawing, but without being restricted to said drawing. Parts not explained in greater detail correspond to parts which are known from DE 10 2006 036 833 A1.

The figures show:

FIG. 1 an oblique view of a plate stack with a cooling channel according to the prior art, and

FIG. 2 a view of a plate stack with two plates according to the prior art, as is depicted in FIG. 1, and

FIG. 3 a view of an inventive plate stack with 3 plates, whereby two cooling channels separated spatially from one another are embodied, and

FIG. 4 a first plate of the plate stack, as depicted in FIG. 3, and

FIG. 5 a second plate of the plate stack, as depicted in FIG. 3, and

FIG. 6 a third plate of the plate stack, as depicted in FIG. 3, and

FIG. 7 a plate without a pattern of recesses which is disposed as a cover plate on top of or underneath the plate stack, and

FIG. 8 a side view of the plate stack with a cover plate on top of the stack and a plate below the stack and connections for supplying and removing fluids to and from cooling channels.

FIG. 1 shows an oblique view of a plate stack 1 with recesses 7 in accordance with the prior art, which has a contiguous cooling channel 8 or a channel for a fluid. The plate stack 1 is constructed from two plates 4 and 5 stacked above one another and enclosed by an upper cover plate 2 and a lower cover plate 3 underneath the plate stack 1, in the form of a sandwich. The two plates 4 and 5 of the plate stack 1 each have Y-shaped recesses 7, which are disposed at regular distances from each other without touching each other. The recesses 7 each produce a regular pattern in a plate 4 or 5. Adjacent plates 4 and 5 are arranged with their recesses 7 so that the recesses 7 only overlap in their edge areas. Each end of a Y-shaped recess 7 of the plate 4 or 5 overlaps with an end, especially with precisely one end, of a Y-shaped recess 7 of the adjacent plate 5 or 4. The overlapping recesses 7 of adjacent plates 4 and 5 form a cooling channel 8 passing completely through plate 4 and 5 along the plate plane.

The cooling channel 8 thus formed can have a fluid flowing through it, with the fluid able to take up and transport away waste heat of the plate 2 and 3. Water provides a frequently-used fluid for cooling. The cooling water flows in the channel 8 in parallel to a plane of plate 2 to 5. The overlapping recesses 7 of adjacent plates 4 and 5 form a pattern which produces a large common surface between the plates 4 and 5 and the fluid. Thus effective cooling is possible with a compact, simple construction. The embodiment of the cooling channel 8 by overlapping recesses 7 in adjacent plates 4 and 5 makes simple production of the channel 8 possible by stacking plates 2 to 5 on top of one another.

FIG. 2 shows a view of a plate stack as presented in FIG. 1. The cross-hatched recesses 7 a are embodied in the first upper plate 4 in the plate stack in a first plane. And the recesses 7 b identified by dots are embodied in the second lower plate 5 in the plate stack in a second plane. The recesses 7 a and 7 b of the first and the second plate 4 and 5 all overlap, but only in the edge area in each case, i.e. at the ends of their Y shape. The pattern of the recesses 7 a in the first plate 4 and the same pattern of recesses 7 b offset thereto in the second plate 5 produces a cooling channel 8 passing right through the length of the plate plane, which takes the form of a network.

FIG. 3 shows a view of an inventive plate stack 1 with 3 plates 4, 5 and 6. The three plates 4 to 6 are stacked above one another and each have a pattern of recesses 7. The recesses 7 are arranged in the plates 4 to 6 such that they form two spatially-separated cooling channels 8 a and 8 b partly lying above one another.

The first plate 4 is shown individually in FIG. 4, with a pattern of recesses 7 a. Shown on the right-hand and left-hand side in the plane of the figure are an inflow 9 and an outflow channel 10. The inflow channel 9 is used to introduce fluid into the first channel 8 a. The outflow channel 10 is used to enable the fluid to leave or to escape from the first channel 8 a. Connections 11 to the inflow channel 9 and the outflow channel 10 are shown as circular dashed areas in each case.

FIG. 5 shows the pattern of the recesses 7 b of the second plate 5. The pattern of the recesses 7 b of the second plate 5, is produced from an overlaying of the pattern of the recesses 7 a of the first plate 4 (see FIG. 4) with the same pattern, rotated through 180 degrees and displaced by a half spacing of the recesses 7 a from each other in each case. Shown cross-hatched on the right-hand and left-hand side in the plane of the figure are the inflow channel 9 and the outflow channel 10 of the third plate 6 arranged below the second plate 5 (see FIG. 6). Circular holes are made in the second plate 5 in order to introduce fluid into the inflow channel 9 or to transport it away via the outflow channel 10 of the third plate 6 (see dashed lines and FIG. 6) via connections 11 through the first and second plate 4 and 5.

The third plate 6 is shown individually in FIG. 6, with a pattern of recesses 7 c. Shown on the right-hand and left-hand side in the plane of the figure are a respective inflow channel 9 and an outflow channel 10. The inflow channel 9 is used to introduce fluid into the second channel 8 b. The outflow channel 10 is used to allow the fluid to leave or to escape from the second channel 8 b. Connections 11 to the inflow channel 9 and to the outflow channel 10 are shown as circles in each case in FIG. 6.

Shown in FIG. 7 is a cover plate 2 (like the cover plate 3) which does not have any pattern of recesses 7. The channels 8 are sealed at the top and bottom with the aid of the cover plate 2 and 3. A cover plate 2 is arranged on top of the plate stack 1 and a cover plate 3 underneath it. The plates 4 to 6 with recesses lie in the shape of sandwich between the cover plates 2 and 3.

The plate stack 1 is shown from the side in FIG. 8. Connections shown in the form of circles in FIG. 7 are shown connected in FIG. 8 to inflow and outflow lines 12. For each of the two channels 8 a and 8 b (not shown in detail in FIG. 8 for the sake of simplicity) an inflow and an outflow 12 are provided in each case, which are disposed in opposite corners of the plate stack. This allows two fluid circuits to be operated separately from one another with the aid of the first and second channel 8 a and 8 b. The two circuits can be used for more even cooling of the plate stack 1 since cool fluid can flow into the plate stack 1 from two different sides. As an alternative the plate stack 1 can be used as a heat exchanger between a fluid with the temperature T₁ and a fluid with a higher temperature T₂.

The plates 2 to 6 shown in the figures as a rule have a thickness in the range of the 1 mm. The channels 8 a and 8 b thus typically likewise have thickness of 1 mm (2 mm at points at which the recesses 7 overlap) in a direction at right angles to the plane of the plates. By stacking identical plates thicknesses of 3 to 30 mm or more of the cooling channels in a perpendicular direction to the plane of the plates can also be realized.

The plates 2 to 6 and cooling channels 8 a and 8 b can however also have other sizes, in the range of a few centimeters thick for example.

The width of the recesses 7 and thus of the channels 8 a and 8 b preferably lies in the range of 5 to 30 mm. Channel widths in the centimeter range are however also possible.

In relation to cooling surfaces with edge lengths in the range of a few centimeters up to around a meter, the thickness of the plates can lie in the range of 0.5 mm-20 mm and the channels can have a thickness in a range of 0.5 mm to 20 mm. Miniature coolers or very large cooling plates can have accordingly modified channel dimensions.

The plates 2 to 6 preferably consist of a metal, especially aluminum or copper. Other pure metals or metal alloys are however also suitable.

Use of the plate stack 1 as a heat exchanger or as a plate stack in a stator plate stack of the machine, such as an electric motor or generator for example, is possible. 

1-16. (canceled)
 17. A device for exchanging heat, the device comprising: a plate stack having at least a first plate, a second plate and a third plate, said at least three plates being stacked above one another and having recesses formed therein and embodied to run through an entire thickness of a respective plate and disposed in a plane of said respective plate in a shape of a regular pattern, said first and second plates, as well as said second and third plates, adjacent to each other in each case, being stacked above one another such that adjacent plates each embody a cooling channel accessible for a fluid along a direction in a plate plane, said recesses in said adjacent plates disposed partly but not completely overlapping, and said cooling channel of said first and second plates being completely spatially separated from said cooling channel of said second and third plates.
 18. The device according to claim 17, wherein said recesses have an identical shape.
 19. The device according to claim 18, wherein said recesses have a Y shape composed of identical pieces rotated by 120 degrees in each case.
 20. The device according to claim 18, wherein said recesses have a Y shape and are disposed in said adjacent plates, and only overlap in an area of ends of said Y shape.
 21. The device according to claim 20, wherein each end of said recesses is disposed overlapped with an end of said Y-shaped recess of said adjacent plate.
 22. The device according to claim 17, wherein at least one of said plates is constructed from a number of identically-shaped part plates stacked to cover a same area above one another.
 23. The device according to claim 17, wherein said plates each have a thickness ranging from 0.5 to 20 millimeters and said channels have a thickness ranging from 1 to 30 millimeters.
 24. The device according to claim 17, wherein said plates are made of a metal.
 25. The device according to claim 17, further comprising cover plates made of a metal and disposed adjacent one of said plates, said plates made of a material selected from the group consisting of plastic and containing a plastic.
 26. The device according to claim 17, wherein said recesses have a Y shape.
 27. The device according to claim 20, wherein each end of said recesses is disposed overlapped with precisely one end of said Y-shaped recess of said adjacent plate.
 28. The device according to claim 17, wherein said plates each have a thickness ranging from 50 micrometers to 1 millimeter and said channels have a thickness ranging from 0.1 to 5 millimeters.
 29. The device according to claim 17, wherein said plates are made of a material selected from the group consisting of magnetizable iron, aluminum and copper.
 30. The device according to claim 25, wherein said metal is selected from the group consisting of aluminum, and copper.
 31. A method for producing a device, which comprises the steps of: stacking at least three plates above one another to form a plate stack such that at least a first cooling channel is formed running right through a first and a second plate of the plate stack and at least one second cooling channel is formed, completely separated spatially from the first cooling channel, passing right through the second and a third plate of the plate stack, the cooling channels being formed in at least one direction in a plate plane by recesses formed in the at least three plates and the recesses of adjacent plates being disposed to partly, but not completely, overlap.
 32. The method according to claim 31, which further comprises forming the recesses by a method selected from the group consisting of punching, drilling, milling, etching and lasing the plates.
 33. The method according to claim 31, which further comprises: forming the recesses in each of the plates in one plane of a respective plate in a form of a regular pattern, and that the first and the third plate are embodied with a same pattern rotated in relation to each other by 90 degrees, and that the second plate disposed between the first and the third plate is embodied with a pattern which is produced by overlaying a pattern of the first plate with a pattern of the third plate, with a displacement of the two patterns in relation to one another.
 34. The method according to claim 31, which further comprises disposing all of the plates of the plate stack so that the recesses of adjacent plates mutually overlap and are not disposed to cover a same area.
 35. The method according to claim 31, which further comprises joining the plates by at least one of gluing, by a snap-lock connection, by soldering or by screwing.
 36. The method according to claim 31, which further comprises flowing a fluid through the cooling channels formed by the recesses.
 37. The method according to claim 31, wherein the at least two cooling channels each have a fluid flowing through them, whereby the two fluid flows differ in temperature and an exchange of heat between the fluid separated from one another takes place via the plates.
 38. The method according to claim 36, which further comprises selecting the fluid from the group consisting of air and water. 